Anode control for plating tanks



March 13, 1951 w. MESSINGER ETAI.

ANODE CONTROL FOR PLATING TANKS 2 Sheets-Sheet 1 Filed March 5l, 1948Flea INVENTORS. WILLIAM MESSINGER DONALD B. L YTLE THE /E ATTORNEYS.

March 13, 1951 w. MEsslNcsl-:R Erm.

ANODE CONTROL FOR PLATIN@ TANKS 2 Sheets-Sheet 2 Filed March 3l, 1948FIGS.

FIG.

INVENTORS. WILLIAM MESSINGER& BYDONALD B. LYTLE Patented Mar. 13, 1951ANODE CONTROL FOR PLATING TANKS William Messinger, Philadelphia, Pa.,and Donald B. Lytle, Bronxville, N. Y.; said Lytle assignor to Time,Incorporated, New York, N. Y., a corporation of New York ApplicationMarch 31, 1948, Serial No. 18,167

1 Claim. (Cl. 204212) The present invention relates to tank structuresfor use in electroplating operations and, more particularly, to animproved tank structure by means of which chromium plating operationsmay be effectively carried out in the plating of large cylindricalobjects.

It has been found, in chromium plating operations, that largecylindrical objects are extremely difficult to plate with a uniformplating of chromium where such objects are supported in a horizontalposition and merely dipped while being ro tated in the plating solutionduring the plating operation. `.'By providing a plating tank which iscapable of supporting such objects ina vvertical position, the objectsmay be `immersed and the plating operation carried out, but where theobjects are of considerable diameter as well as length, the problem ofmaintaining a desired and uniform current density has presented aserious obstacle to plating operations of objects in the verticalposition, as above described.

It is an object of the present invention, accordingly, to provide aplating tank structure which is of such formation as to permit longobjects,

`such as cylinders, to bereceived and supported in a vertical positionduring the plating operation and, while so supported, providing meanswhereby the current density of the surface being plated is eiectivelycontrolled.

Yet another object of the present invention is to provide a plating.tank structure of the above character wherein large and long cylindersmay be supported in a vertical position during plating operations androtated while in such position, the invention further contemplating theprovision of means for controlling the area of the object that issubjected to the plating operation during rotation, as well ascontrolling the current density as desired.

Further objects of the invention will be apparent as it is described ingreater detail in connection with the accompanying drawings, whereinFigure 1 is a view in vertical section taken through a plating tankconstructed in accordance with the present invention, the View beingtaken on the plane indicated at I-l of Figure 2 and looking in thedirection of the arrows;

Figure 2 is a plan View of the tank structure shown in Figure 1;

Figure 3 is a View similar to Figure 1, showing a modified form ofanode;

Figure 4 is a view in horizontal section, taken on the line 4 4 ofFigure 3, and looking in the direction of the arrows; and

, Figure 5 is an enlarged. view of the mechanism at the bottom of thetank shown in Figure 3.

Referring to the above drawings, a plating tank is illustrated as beingformed with an outer shell I I having a plurality of reinforcingstructural channel members IIa secured thereto, together with a topangle flange I2 and a bottom plate I3. The'bottom plate I3 may be formedwith a well I i within which the bottom extremity of the object beingplated may be received. For example, if a large cylinder Il) is beingplated, the cylinder shaft maybe received within the Well I4 thus toremove it from the active plating area within the tank.

A suitable liner I5 of lead or other inert material is provided withinthe shell II and formed and secured in such position that the shell iseffectively sealed from the plating solution contained Within the tankduring the plating operation. vertically extending reinforcing anglebarsI6 may be provided, as will be well understood by those skilled in theart. A suitable supply of a, plating solution may be provided throughinlet and outlet pipes Il and I8, respectively, all in accordance withknown plating practice. An overflow pipe I8 is provided adjacent the topof the tank.

In accordance with the present invention and in order to provideeifective control for the plating of large objects, such as cylinderIll-I, the tank I I is provided with an anode bay I9 Within which ananode 20 is received. At the entrance to the bay, doors 2l and 22 areprovided, the doors being pivoted on vertical hinges at 23 and 24,respectively. In this fashion the doors may be swung into the tank, asillustrated in Figure 2, the adjustable position of the doors permittingthe effective area of the entrance to the bay to be varied in order torestrict the area of plating that is accomplished upon the objectcarried within the plating tank I I. Shields 26 and 2l formed of inertmaterial are provided in the bay to control the plating operation toproduce a plate of even thickness by increasing the length of theelectric current path'from the anode to the cylinder ends, therebyavoiding the heavy build-up of plating that would otherwise take placeat the ends of the cylinder.

It will be understood that suitable means forming no part of the presentinvention is to be pro-V,

vided to support and rotate the cylinder within the tank I I so that theentire cylindrical surface to be plated is progressively broughtopposite the anode bay I9, and thus in the continuous rotation a platingof uniform thickness and character is built up during the platingoperation. The anode 20 is positioned within the anode bay by means ofspacers 25 and is suitably connected to a source of electricity to whichthe object being plated is also connected, all in accordance withstandard plating practice. By controlling the position of the doors 2|and 22, the exposed area of the cylinder or other object'` being platedis effectively controlled. Furthermore, since it is well known thatthere is a xed relationship between current density and temperature ofthe electrolyte bath and that the heat generated by the electroplatingcurrent is considerable, it is possible, by determining the tempera-tureofthe bath and adjusting the position of the doors 2| and 22, tomaintain the required current density to eiect the desired platingoperation..

In the form of the invention shown in Figures 3, 4, and 5, the anode 28is shown as being provided with an intermediate portion 29 havingportions 30 that incline away from the cylinder l0, and in this fashion,serve to control the platingoperation so that the thickness of the plateis uniform to the ends of the cylinder.

In the well I4 of the tank, a guide bearing 3| is provided havingv aAbase plate 32 which iS mounted in a similarly shaped recess 33 in asecond plate 3B. The plate 32 is rotatable in the recessy 33, the recessbeing formed eccentrically with respect to the Vertical aXis of theplate 35. VIn this fashiorh the vertical axis of the cylinder I0 may beadjusted se that the periphery of the cylinder may be properly spacedwith respect to the anode within the anode bay I9. By fori-ning thebearing 3| with a desired eccentricity with respect to the plate 32,careful adjustment of the position of the cylinder may be accomplished.

It is also within the contemplation of this invention to adjust thedistance between the anode and the cylinder, and thus regulate theintensity of the plating current, by moving the` anode horizontallytoward or away fromthe cylinder. This may be accomplished in anysuitable manner such as, for example., by suspending the anode 'from twohorizontal copper bars upon which the anode is slideably adjustable, andlocking them securely together after the adjustment has. been made.

While the invention has been described with specific reference to thestructure shown in the accompanying drawings, it is not to be limitedsave as dened in the appended claim.

We claim:

A tank for plating elongated cylinders comprising an elongatedvertically disposed tank structure for containing an electrolyte and anelongated cylinder, a vertically disposed bay extending outwardly of andopening into the tank at oneT side thereo, an anode in the bay, meansfor adjusting the position of the anode in the bay, a door between thebay and the tank, a well in the bottom of the tank, a plate mounted forrotation inthe well,Y and a bearing mounted on the plate for eccentricrotation with reference to the plate, and for receiving one end of anelongated cylinder, the door being supported for rotation about avertical axis to. vary the effective width of the entrance into the` bayduring a plating operation and thereby control the current density undervarying conditions of temperature the electrolyte, the plate in the wellbeing rotatable to adjust the distance between the anode and thecylinder to be plated, and the cylinder supporting bearingV beingrotatable relative to the plate for rotating the cylinder within thetank during the plating operation.

WILLIAM MESSINGER. DQNALD B. LY'ILE.

REFERENCES CITED The following references are, of record` in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 680,408 Cowper-,Coles Aug. 13,1901 1,519,572 Wolf Dec. 16, 1924 2,086,226 Hoff July 6, 1937 2,155,392Ballard Apr. 25', 1939 FOREIGN' PATENTS Number Country i Date 712,505France A July 21, 1931

